[tex4ht] SVG production

[Michal Hoftich]

Hi all, 

Fredrick Brennan on TeX.sx [1] pointed out that SVG plugin for Pstoedit
is shareware and it isn't therefore included in distributions. This
explains why it didn't work I suppose :)

Anyway, it doesn't make sense to use DVI -> PS -> SVG route anymore,
since we have dvisvgm, which is included in all TeX distributions, so I
updated tex4ht-env.tex to use it. I added it to both Unix and Windows
versions.

Another question: does it still make sense to use Dvips and GS for PNG
conversion? Shouldn't we use Dvipng by default? It produces much better
results.

Best regards,
Michal

[1] http://tex.stackexchange.com/q/351535/2891